-No Healing Touch - 100
-Completed with 90 left - 500
-No mistakes - 900
-Max chain over 70 - 500
Interestingly enough, Deftera is one extreme operation in which stalling isn't recommended. Because of this, XSing it isn't very hard. All you have to do is kill it as fast as you can and you will most likely have the points needed for the rank. The points you need are close to 8000 though you can score a bit below that and still get the XS.
This operation will work in two parts. First the stomach with a single Deftera, and then in the lung with 2 Deftera.
When you get inside the patient's stomach you'll be greeted by 6 tumors. Laser them all quickly. If you do it fast enough they won't have a chance to create little ones. Remember that we will never stall throughout this operation. The only possible exception is in the very unlikely scenario that you finish with less than a chain of 70. Don't even worry about this though, since, like I said, it probably won't happen.
Now the Deftera type A and type B are going to run around for a while and create tumors every now and then. Keep your laser on hand and burn them off immediately when they appear. Try not to give them a chance to create tiny ones or to stick around for too long since it hurts the patient's vitals. After a little while (or a long while depending on your luck), the Deftera type A and type B will meet and begin eating each other. Now before you do anything, make sure that you've burned off any tumors that may have been created. Switch to your drain and keep it steady over the colliding Deftera. Keep the button pressed. You should do it fast enough that it takes a while for the drain to start working. Like I said, don't drain the Deftera if there are still tumors around. This will cause the drainage to fail and it will just be wasted time. Pools of blood will form periodically so drain them when you get the chance. If you're currently draining a Deftera or burning a tumor and a pool forms somewhere, just ignore it until you're done. The only exception is if the pool is obstructing the tumor or the Deftera.
You'll need to drain the Deftera 3 times, so repeat the same procedure twice again. When you drain for the third time, quickly change to your scalpel. Circular scalpel lines will appear that will allow you to excise the Deftera. It gives you a little bit of time to get ready before the lines appear, so what I'd recommend is to start moving the scalpel where you THINK the lines will appear before they do so that you waste no time, and also so you're already comfortably making the right motion. Don't cut too fast because you want to get every dot on the first pass. If you do this fast enough the Deftera will only get a chance to create a single tumor. Burn this tumor off before you grab the Deftera with the forceps and place it on the tray. Then simply apply the synthetic membrane and gel over it. If you're fast you can inject a single round of stabilizer before the screen fades. It's the same patient so vitals carry over. Make the suture and apply the bandage. Make sure you never break your chain even once.
Now we'll move on to the lung. Be careful with the lobectomy here. It's not a straight line. Once inside, you'll have to deal with 2 Deftera.
The procedure is basically the same as the last one, except, obviously, there's going to be double the amount of tumors that you have to laser off, and the vitals will drop much quicker because when two of the same type meet they cause a nice bit of damage. Basically what you want to do here is, while the Deftera are moving around, burn off any tumors that get created immediately, and in between this, when there are no tumors present, be draining off blood pools and injecting stabilizer. The window of opportunity when there are no tumors present is very small so you'll have to be fast with that syringe. The main thing here is that you should ALWAYS be: either burning off tumors, or draining blood, or injecting stabilizer. Never catch yourself doing nothing unless vitals are at 99. Since there are two Deftera, there is a chance that while you're draining one, the other creates tumors which can screw you up. But don't despair. Simply continue taking care of the tumors and wait for your chance when both pairs of types are eating each other.
After a while, a type A and type B should meet. When this happens, the chances of the other pair meeting are very, very high. So what you want to do is drain both of them one right after the other. But first make absolutely sure that there are no tumors present, otherwise it won't work. Do this two more times, but on the third drain, don't drain the second pair. Instead switch to the scalpel and excise the first Deftera like you did back in the stomach. Remove it, apply the synthetic membrane, and gel. By this time the other pair has probably separated and started moving again. This is fine. Just keep working like you have up till now and when they meet, drain and excise them like normal. If all has gone well your chain should be above 70 and the clock should be around 3:00. This will net you the XS almost guaranteed.