I have seen a video of someone deglosating a sentence. The original sentence was アリスはすぐ下に落ちた which can translate to "Alice soon fell below". But when I saw the sentence, I thought the に particle could be used as アリスはすぐに下に落ちた. I don't know if this is too redundant or if it's correct at all, but I was confused with the fact that に was not used with すぐ this time.
Also, I tried removing the particle completely and I thing it may make sense. It turns out like this: アリスはすぐ下落ちた.
Anyways, any explanation on the topic is appreciated.