Action: Sacrifice a development to reveal the top card of your deck. If the revealed card is a support card, put it into play and deal damage equal to its printed cost to this unit. Otherwise, discard it.
Can you use Engineer's action to respond to itself and sacrifice for example: 5 developments to search top 5 cards of your deck and put all found suppports in play despite Engineer dying in the process (you find 3 two cost supports, will the engineer be able to put all into play?).
Virgo said:
Action: Sacrifice a development to reveal the top card of your deck. If the revealed card is a support card, put it into play and deal damage equal to its printed cost to this unit. Otherwise, discard it.
Can you use Engineer's action to respond to itself and sacrifice for example: 5 developments to search top 5 cards of your deck and put all found suppports in play despite Engineer dying in the process (you find 3 two cost supports, will the engineer be able to put all into play?).
Yes, you can do that.
You can trigger the action as many times as you want, in response to each other, as long as you can sacrifice a development each time. That is the only cost. Damaging the engineer is just something that happens when the effect resolves.
Its not really "searching" the top 5 cards though. You just reveal them one at a time as you resolve the Action chain, and either discard them or put them into play and damage your engineer.