Some pretty good advice and I don't have to add much.I really admire your ethics and concern.Stuff does happen,no matter how hard we try and I believe you can improve the odds if you decide to stick with it.We don't have a pin or a bead to put on that "spot" and under stress,our concentration often isn't as focused as when we are shooting in the yard.
Regarding the issue of possible string jump,I have to ask,did you grunt to stop either deer.
That is a popular method these days and it puts deer on high alert before the shot.I like a standing deer myself but if a deer is walking and I feel I can make the shot,I will give it a very small lead and shoot.As much as I prefer a shot at a standing,relaxed deer,even they have a better chance to jump than a deer moving forward.
The walking deer is making noise and has to reverse directions to drop and bolt.Stopping deer and shooting at them with a weapon that shoots a projectile only 170 fps or even 300,can lead to a miss or much worse.
Stopping a deer when using a weapon that shoots 800 fps or more is a whole different ball game.Just some food for thought and that shot can be easily practiced with the help of a friend,a long rope and a milk jug.
Well whatever you decide,good luck.I'm impressed with your attitude and know you will work it out.