to kill the toaster, max your stats and constantly use special from the beginning, keep on him, even when he runs into you, i managed to kill him after 2 tries, after i maxed
for any of the mission have you last 5-10 minutes, just do this. stop shooting, if you stop killing enemies, they wont respawn, instead the remaining enemies end up just bunching up, then just circle them, and run out the clock.
Thank you Inferno11