The targeted opponent chooses which of their attacking creatures to sacrifice, not you.

Untapping an attacking creature doesn’t cause it to be removed from combat.

You choose all of your modes at once. You can’t wait to perform one mode’s actions and then decide to choose more modes.

You can’t choose any one mode multiple times.

If two of the chosen modes of an escalate spell target a creature, you may choose the same creature for each mode’s target, or choose different creatures. The same is true if the chosen modes target a player (or opponent).

If one target of an escalate spell becomes illegal, the other targets will still be affected. If all of the targets become illegal, the spell won’t resolve.

Effects that reduce the cost of spells reduce the total cost, including any escalate costs added.

If an effect allows you to cast a spell that has escalate without paying its mana cost, you pay escalate costs for that spell if you choose more than one mode.

Additional costs don’t affect a spell’s mana value.