That is so cute! I have had hamsters before and never heard them sound like that. We did have five gerbils once - rescued one from a pet store that we found in an enclosure with large rats, then went to the pet store a few months later to find a her a playmate and ended up bringing two more home, then later another trip to the pet store found us with two more. They ended up in three different cages because they fight with unfamiliar gerbils.
Sorry - to get to the point, gerbils will "stomp" their feet when they are alarmed. Ours would do it to get our attention. We had them on tables and a desk and would let them run around outside their cages on the tables when we were home so as soon as we walked in the door from work and we did not immediately let them out they would start stomping at us, one would start and the rest would follow suit. Also, they would squeak really loud sometimes when they were unhappy. Spoiled buggers they were.