So you agreed because you are afraid.
You let yourself be crippled by your doubt. So very fearful of making the wrong choice, you effectively refuse to act on your own terms, pushed along the currents of fate with no resistance.
Do you feel like you are doing something wrong?
That being here with me, right now, is wrong?
BLUE GUY: I guess I'm always kind of afraid of messing something up-
BLUE GUY: I mean- this is a big deal right-?
BLUE GUY: I don't even know what any of this means- let alone do I feel confident enough to handle it-

But what is your alternative?
Would you rather return to your old life?
Would you rather live out the rest of your days stitching bodies back together, hoping against hope that the next one you find will not be of someone you care about?
Look at yourself.
In this tale I weave before you, it becomes clearer with every word that you care deeply about those who do not care for themselves.
Death is familiar company in the world you live in, and healthy minds are few and far between.
And without this deal of ours, the cycle of existence itself would be broken by a force of total annihilation.
You are far better equipped to handle this than you know. Maybe even more than I know, if only because you have no other options.
You are, in many ways, at the end of your rope. In much the same way, I am nearing the end of mine.
Take these words of advice, if nothing else: there are some instances in life when it is blissful to be ignorant.
True understanding can beget torment for the mind, leaving initiative at the mercy of atrophy.
The more you understand, the more difficult it is to act.
And we cannot risk indecisiveness when so much is at stake.
Just remember what I have told you. The rest shall become clear whenever it needs to be so.
BLUE GUY: To be honest- that freaks me out a little-
BLUE GUY: I suppose I don't have much of a choice at this point-
BLUE GUY: I did make a promise-