If On Thin Ice leaves the battlefield before its triggered ability resolves, the target creature won't be exiled.
2019-06-14 • wotc
Auras attached to the exiled creature will be put into their owners' graveyards. Any Equipment will become unattached and remain on the battlefield. Any counters on the exiled creature will cease to exist.
2019-06-14 • wotc
If a token is exiled this way, it will cease to exist and won't return to the battlefield.