alarm went off in a level exam

we had our exam in a classroom so everyone had to bring bags inside the room as there was no cloakroom etc and younger years were running about outside. i left my phone at the back of the room with my bags on silent and airplane mode but some random alarm went off. i said it was my phone and they wrote down my candidate nummber. will i be disqualified?? or marks lost? it was at the back with everyones bags which also wouldve had their phones in.. the invigilator said it would be fine she just had to write it down, but after googling similar situations i am getting stressed