Using Multiple SendKeys Functions At the Same Time?

I'm using visual basic 6 and I use autoitx3 Lib.

Dim Command As New AutoItX3Lib.AutoItX3

Command.Send "h"
sleep 100
Command.Send "e"
sleep 100

Command.Send "l"
sleep 100

Command.Send "l"
sleep 100

Command.Send "o"

When I put this code on a button click event, it works perfect but when I use another button,


Command.Send "w"
sleep 100

Command.Send "o"
sleep 100

Command.Send "r"
sleep 100

Command.Send "l"
sleep 100

Command.Send "d"
sleep 100

and put this codes on its click event, when I click the second button right after I clicked the first one,

it waits for the "hello" to write "world". It's not like "hweolrllod".

How can I do this?